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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 847 records · Page 47
All sourcesNASA NTRSDOE OSTI
DOE OSTI2014

SU-E-J-176: Results of Images Acquired with Backscattered MV Radiation Using a Pinhole Collimator

Purpose: To ascertain the feasibility of acquiring real time images of small lung tumors from scattered photons while undergoing radiation treatment.There are several methodologies currently used to track tumor location such as MV-cine acquisition and kV fluoroscopy. However, MVcine offers no information parallel to the beam axis while kV fluoroscopy offers little potential for soft tissue discernability while also increasing the patient dose. This study investigates the feasibility of observing an actual simulated tumor while exploring techniques that may improve image quality. Methods: A prototype imager consisting of a gamma camera pinhole collimator and a computed radiography (CR) plate were used in conjunction with a Varian TrueBeam linac. One study consisted of a 2.5 cm diameter solid water cylinder representing a solid tumor imbedded within a lung equivalent material slab. The cylinder with the lung slab was sandwiched between 1 cm lung equivalent slabs and these were sandwiched between 2 slabs of solid water. The top water slab was 1 cm thick. The other imaging study consisted of three different density plugs, 0.46, 1.09, and 1.82 g/cm3 placed on the accelerator couch. The gantry was orientated 70° relative to the CR plate. The slabs and plugs were irradiated with 2000 MU and 500 MU respectively using the 6FFF mode. Results: The solid water plug was visually discernible in the slab phantom. The ratio of the signal coming from the higher density plugs (placed on the treatment couch) to that between the plugs increased from 1.02 to about 3.0 after subtracting the background image acquired with no plugs present. Conclusion: Preliminary results indicate that a lung tumor could be visualized with scattered radiation during treatment. Improvements in discerning an object can be enhanced by filtering out the head leakage and background scattered radiation not emanating from the imaged object.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2015

Inline CBET Model Including SRS Backscatter

Cross-beam energy transfer (CBET) has been used as a tool on the National Ignition Facility (NIF) since the first energetics experiments in 2009 to control the energy deposition in ignition hohlraums and tune the implosion symmetry. As large amounts of power are transferred between laser beams at the entrance holes of NIF hohlraums, the presence of many overlapping beat waves can lead to stochastic ion heating in the regions where laser beams overlap [P. Michel et al., Phys. Rev. Lett. 109, 195004 (2012)]. Using the CBET gains derived in this paper, we show how to implement these equations in a ray-based laser source for a rad-hydro code.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2021

Indoor Occupant Counting by RF Backscattering

Building HVAC (heating, ventilation and air conditioning) consumes approximately 13% of all energy consumption in USA. Motion detectors, cameras and user programmable thermostats have been shown to be ineffective for HVAC controls to save energy, mostly due to the user concerns of comfort, reliability and privacy. A new HVAC control system based on real-time occupant counting that is fully automated, highly accurate, economically sensible and preserving privacy and aesthetics can thus bring forth a disruptive impact to this large energy sector. Our indoor occupant monitoring technology is based on the radio-frequency identification system (RFID), deployed in the room, not on the occupants. One reader with four antennas can be deployed on the ceiling or behind the ceiling panels for every thousand square feet in home, office and assisted living, with or without room partitions. The sticker-like passive tag, 10 cents each and maintenance-free, are profusely hidden on the wall or inside the furniture at arbitrary position, preserving privacy and aesthetics. The large number of tags can realize diverse observation points to accommodate arbitrary room layouts, which is impractical by other active units of camera, infrared, radar or lidar. With 20 tags, the system can reliably detect the number of occupants. For 100 tags, occupant posture and location can be known. The technology has been verified in the research labs and test buildings with very high accuracy. When the real-time occupant number can be accurately known without assuming devices on occupants or occupant motion, the building HVAC system can be automated to achieve building energy saving without sacrificing occupant comfort. According to our limited testing in a few types of building models and the simplified cost calculation, the RFID system has low overall cost in production, deployment, operation and maintenance. The signal processing algorithm based on machine learning requires very small number of training cases as most learning is transferrable for various layouts, and very low computational needs during operation, according to our testing in four different room sizes and layouts. In our preliminary estimate from HVAC saving alone, the RFID system can potentially pay for itself within 1.5 years, in addition to the other enhancement in building automation systems (BAS). Our commercialization strategy and business pitch deck focus on venturing this Cornell occupant monitoring technology into BAS and energy management markets. We have identified three broad BAS market segments of senior living, residential buildings, and office buildings. We have put together the minimum viable product characteristics for these identified segments, including analyses on total cost and competing technologies, as well as the fit and technical gaps for these market segments. We intend to bring the technology to market by licensing or partnering with existing BAS vendors. A list of potential collaborators and licensing partner candidates was assembled for different aspects of integrating our technology into a potential product that can be used with BAS.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2025

The Measurement of Grain Size by Electron Beam Backscattered Diffraction

The method of electron back-scatter diffraction provides an analytic means to identify crystalline phase and the grain size of structural materials. The need to utilize imaging parameters consistent with revealing the contributing microstructural scale is often overlooked through packaged imaging scripts. It is shown that imaging parameters consistent with a post processing assessment of low misorientation angles between boundaries are achievable as using pixel sizes on the order of 10 1 nm.

36 MATERIALS SCIENCE↗